SES crews and police spent yesterday dealing with the aftermath of 52.2mm of rain, since Wednesday, and strong winds which resulted in more than 250 calls for help and stranded cars on roads turned into rivers.

The inclement weather was blamed for stopping an air ambulance called to transport a woman critically injured after being struck by a car in Ballarat's CBD early yesterday morning.

The Sebastopol woman was in a critical condition in The Alfred hospital yesterday after she was struck by the car in Drummond Street South about 2.35am.

The woman was believed to have been walking in the middle of the street when the she was hit.

Police said the driver was a 27-year-old Ballarat man who stopped at the scene and then returned "a positive evidential breath test".

Yesterday he was assisting police with their inquiries and was expected to be charged on summons.

The 39-year-old woman was rushed to Ballarat Health Services Base Hospital before she was driven by ambulance to The Alfred with a ruptured aorta.

Ambulance Victoria had attempted to evacuate the woman by helicopter but it was unable to land in Ballarat because of wild weather.

"It got half way to Ballarat and couldn't get in because of the low cloud," Ambulance Victoria spokesman John Mullen said.

The accident occurred amid the storm which resulted in more than 125 SES volunteers working during the last 48 hours.

Roads around Napoleons and Haddon were still flooded yesterday with several cars left stranded as streams of water made for treacherous driving conditions.

Last night the SES continued to receive calls for help mostly reporting fallen trees and some property damage.

SES regional duty officer Mark Cattell said the service had received 252 calls for help _ mostly from Ballarat - since 11am Wednesday.

There were 63 calls to the SES from Ararat and 24 from Hepburn.